Multi-speed transmission having a stacked planetary gear set

ABSTRACT

A transmission of the present invention has an input member, an output member, two planetary gear sets, a planetary gear set assembly, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The planetary gear set assembly is a stacked planetary gear set that includes a first, second, third and fourth member. The torque transmitting devices may include clutches and brakes. The torque transmitting devices are each selectively engageable in combinations of at least three to establish at least eleven forward speed ratios and at least one reverse speed ratio.

FIELD

The invention relates generally to a multiple speed transmission having a plurality of planetary gear sets and a plurality of torque transmitting devices, and more particularly to a transmission having eleven or more speeds, two planetary gear sets, a planetary gear set assembly and a plurality of torque transmitting devices.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.

A typical multiple speed transmission uses a combination of friction clutches or brakes, planetary gear arrangements and fixed interconnections to achieve a plurality of gear ratios. The number and physical arrangement of the planetary gear sets, generally, are dictated by packaging, cost and desired speed ratios.

While current transmissions achieve their intended purpose, the need for new and improved transmission configurations which exhibit improved performance, especially from the standpoints of efficiency, responsiveness and smoothness and improved packaging, primarily reduced size and weight, is essentially constant. Accordingly, there is a need for an improved, cost-effective, compact multiple speed transmission.

SUMMARY

A transmission is provided having an input member, an output member, two planetary gear sets, a planetary gear set assembly, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The planetary gear set assembly is a stacked planetary gear set that includes a first, second, third and fourth member. The torque transmitting devices are for example clutches and brakes.

In an aspect of the present invention, an output member is continuously interconnected with the second member of the planetary gear set assembly.

In another aspect of the present invention, a transmission is provided having a first interconnecting member for continuously interconnecting the second member of the first planetary gear set with the first member of the second planetary gear set.

In yet another aspect of the present invention, a transmission is provided having a second interconnecting member for continuously interconnecting the third member of the first planetary gear set with the second member of the second planetary gear set and with the first member of the planetary gear set assembly.

In yet another aspect of the present invention, a transmission is provided having a first torque transmitting device for selectively engaging the second member of the first planetary gear set and the first member of the second planetary gear set with the input member.

In yet another aspect of the present invention, a transmission is provided having a second torque transmitting device for selectively engaging the first member of the first planetary gear set with the input member.

In yet another aspect of the present invention, a transmission is provided having a third torque transmitting device for selectively engaging the third member of the planetary gear set assembly with the input member.

In yet another aspect of the present invention, a transmission is provided having a fourth torque transmitting device for selectively engaging the third member of the second planetary gear set with the stationary member.

In yet another aspect of the present invention, a transmission is provided having a fifth torque transmitting device for selectively engaging the first member of the second planetary gear set with the stationary member.

In yet another aspect of the present invention, a transmission is provided having a sixth torque transmitting device for selectively engaging the first member of the first planetary gear set with the stationary member.

In yet another aspect of the present invention, a transmission is provided having a seventh torque transmitting device for selectively engaging the fourth member of the planetary gear set assembly with the stationary member.

In still another aspect of the present invention, the torque transmitting devices are each selectively engageable in combinations of at least three to establish at least eleven forward speed ratios and at least one reverse speed ratio between the input member and the output member.

In still another aspect of the present invention, the first member of the first planetary gear set, the third member of the second planetary gear set, the first member of the planetary gear set assembly are sun gears, the second member of the first planetary gear set, the first member of the second planetary gear set, the second member of the planetary gear set assembly are carrier members wherein the carrier member of the second planetary gear set rotatable supports a first and second set of planet pinions and wherein the first set of planet pinions mesh with the sun gear and the second set of planet pinions and the second set of planet pinions mesh with the ring gear and the first set of planet pinions and the third member of the first planetary gear set, second member of the second planetary gear set, the third member of the planetary gear set assembly are ring gears.

In still another aspect of the present invention, the fourth member of the planetary gear set assembly is a gear having an outer surface and an inner surface, wherein the outer surface has a plurality of gear teeth and the inner surface has a plurality of gear teeth.

In still another aspect of the present invention, the fourth member of the planetary gear set assembly meshes with a first plurality of pinion gears rotatably supported by the second member of the planetary gear set assembly and with a second plurality of pinion gears rotatably supported by the second member of the planetary gear set assembly

Further features, aspects and advantages of the present invention will become apparent by reference to the following description and appended drawings wherein like reference numbers refer to the same component, element or feature.

DRAWINGS

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of an eleven speed transmission according to the present invention;

FIG. 2 is a diagrammatic view of an embodiment of an eleven speed transmission according to the present invention;

FIG. 3 is a diagrammatic view of another embodiment of an eleven speed transmission according to the present invention; and

FIG. 4 is a truth table presenting the state of engagement of the various torque transmitting elements in each of the available forward and reverse speeds or gear ratios of the transmission illustrated in FIGS. 1, 2 and 3.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that in the particular example provided, the eleven speed automatic transmission of the present invention has an arrangement of permanent mechanical connections between the elements of the four planetary gear sets. A second component or element of a first planetary gear set is permanently coupled to a first component or element of a second planetary gear set. A third component or element of the first planetary gear set is permanently coupled to a second component or element of a second planetary gear set and to a first component or element of a fourth planetary gear set and to a first component or element of a third planetary gear set. A second component or element of a fourth planetary gear set is permanently coupled to a third component or element of a third planetary gear set and to the input member.

Referring now to FIG. 1, an embodiment of an eleven speed transmission 10 is illustrated in a lever diagram format. A lever diagram is a schematic representation of the components of a mechanical device such as an automatic transmission. Each individual lever represents a planetary gear set wherein the three basic mechanical components of the planetary gear set are each represented by a node. Therefore, a single lever contains three nodes: one for the sun gear, one for the planet gear carrier and one for the ring gear. The relative length between the nodes of each lever can be used to represent the ring-to-sun ratio of each respective gear set. These lever ratios, in turn, are used to vary the gear ratios of the transmission in order to achieve appropriate ratios and ratio progression. Mechanical couplings or interconnections between the nodes of the various planetary gear sets are illustrated by thin, horizontal lines and torque transmitting devices such as clutches and brakes are presented as interleaved fingers. If the device is a brake, one set of the fingers is grounded. Further explanation of the format, purpose and use of lever diagrams can be found in SAE Paper 810102, “The Lever Analogy: A New Tool in Transmission Analysis” by Benford and Leising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a first planetary gear set 14 having three nodes: a first node 14A, a second node 14B and a third node 14C, a second planetary gear set 16 having three nodes: a first node 16A, a second node 16B and a third node 16C, a third planetary gear set 18 having three nodes: a first node 18A, a second node 18B and a third node 18C, a fourth planetary gear set 20 having three nodes: a first node 20A, a second node 20B and a third node 20C and an output shaft or member 22.

The second node 14B of the first planetary gear set 14 is coupled to a first node 16A of the second planetary gear set 16. The second node 16B of the second planetary gear set 16 is coupled to third node 14C of the first planetary gear set 14. The third node 14C of the first planetary gear set 14 is coupled to the first node 20A of the fourth planetary gear set 20. The first node 20A of the fourth planetary gear set 20 is coupled to the first node 18A of the third planetary gear set 18. The third node 18C of the third planetary gear set 18 is coupled to the second node 20B of the fourth planetary gear set 20.

A first clutch 26 selectively connects the first node 16A of the second planetary gear set 16 and the second node 14B of the first planetary gear set 14 with the input shaft or member 12. A second clutch 28 selectively connects the first node 14A of the first planetary gear set 14 with the input shaft or member 12. A third clutch 30 selectively connects the second node 18B of the third planetary gear set 18 with the input shaft or member 12. A first brake 32 selectively connects the third node 16C of the second planetary gear set 16 with the stationary element or a transmission housing 50. A second brake 34 selectively connects the second node 14B of the first planetary gear set 14 with the stationary element or a transmission housing 50. A third brake 36 selectively connects the first node 14A of the first planetary gear set 14 with the stationary element or a transmission housing 50. A fourth brake 38 selectively connects the third node 20C of the fourth planetary gear set 20 with the stationary element or a transmission housing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout of the embodiment of the eleven speed transmission 10 according to the present invention. In FIG. 2, the numbering from the lever diagram of FIG. 1 is carried over. The clutches, brakes, and couplings are correspondingly presented whereas the nodes of the planetary gear sets now appear as components of planetary gear sets such as sun gears, ring gears, planet gears and planet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14A, a ring gear member 14C and a planet gear carrier member 14B that rotatably supports a set of planet gears 14D (only one of which is shown). The set of planet gears 14D are each configured to intermesh with both the sun gear member 14A and a ring gear member 14C. The sun gear member 14A is connected for common rotation with a first shaft or interconnecting member 42. The ring gear member 14C is connected for common rotation with a second shaft or interconnecting member 44 and with a third shaft or interconnecting member 46. The planet carrier member 14B is connected for common rotation with a fourth shaft or interconnecting member 48 and with a fifth shaft or interconnecting member 52.

The planetary gear set 16 includes a sun gear member 16C, a ring gear member 16B and a planet gear carrier member 16A that rotatably supports a first set of planet gears 16D (only one of which is shown) and a second set of planet gears 16E (only one of which is shown). The first set of planet gears 16D are each configured to intermesh with both the sun gear member 16C and the second set of planet gears 16E. The second set of planet gears 16E are each configured to intermesh with both the ring gear member 16B and the first set of planet gears 16D. The sun gear member 16C is connected for common rotation with a sixth shaft or interconnecting member 54. The ring gear member 16B is connected for common rotation with the second shaft or interconnecting member 44. The planet carrier member 16A is connected for common rotation with the fourth shaft or interconnecting member 48 and a seventh shaft or interconnecting member 56.

The planetary gear set 18 and planetary gear set 20 are configured to form a stacked planetary gear set assembly 21. Stacked planetary gear set assembly 21 includes a sun gear member 18A, a ring gear member 20A, a common member 21A and a combined planet gear carrier member 21B. Combined planet gear carrier member 21B rotatably supports a first set of planet gears 21C (only one of which is shown) and a second set of planet gears 21D (only one of which is shown). The sun gear member 18A is connected for common rotation with the third shaft or interconnecting member 46. The ring gear member 20A is connected for common rotation with an eighth shaft or interconnecting member 58. The common member 21A is connected for common rotation with a ninth shaft or interconnecting member 60. The common member 21A is preferably a unitary gear member that has an inner surface that has internal gear teeth and an outer surface that has external gear teeth. The internal gear teeth of common member 21A are configured to mesh with the first set of planet gears 21C and the outer gear teeth are configured to mesh with the second set of planet gears 21D. The combined planet carrier member 21B is connected for common rotation with the output shaft or member 22. The first set of planet gears 21C are each configured to intermesh with both the sun gear member 18A and the common member 21A. The second set of planet gears 21D are each configured to intermesh with both the ring gear member 20A and the common member 21A.

The input shaft or member 12 is continuously connected to an engine (not shown) or to a turbine of a torque converter (not shown). The output shaft or member 22 is continuously connected with the final drive unit or transfer case (not shown).

The torque-transmitting mechanisms or the clutches 26, 28, 30 and the brakes 32, 34, 36 and 38 allow for selective interconnection of the shafts or interconnecting members, members of the planetary gear sets and the housing. For example, the first clutch 26 is selectively engageable to connect the fifth shaft or interconnecting member 52 with the input shaft or member 12. The second clutch 28 is selectively engageable to connect the first shaft or interconnecting member 42 with the input shaft or member 12. The third clutch 30 is selectively engageable to connect the eighth shaft or interconnecting member 58 with the input shaft or member 12. The first brake 32 is selectively engageable to connect the sixth shaft or interconnecting member 54 with the stationary element or the transmission housing 50 in order to prevent the sixth shaft or interconnecting member 54 from rotating relative to the transmission housing 50. The second brake 34 is selectively engageable to connect the seventh shaft or interconnecting member 56 with a stationary element or the transmission housing 50 in order to prevent the seventh shaft or interconnecting member 56 from rotating relative to the transmission housing 50. The third brake 36 is selectively engageable to connect the first shaft or interconnecting member 42 with the stationary element or the transmission housing 50 in order to prevent the first shaft or interconnecting member 42 from rotating relative to the transmission housing 50. The fourth brake 38 is selectively engageable to connect the ninth shaft or interconnecting member 60 with the stationary element or the transmission housing 50 in order to prevent the ninth shaft or interconnecting member 60 from rotating relative to the transmission housing 50.

With reference to FIG. 3, an alternate embodiment of an eleven speed transmission 100 of the present invention is illustrated schematically. Transmission 100 has the same number of planetary gear sets, clutches and brakes interconnecting members of the planetary gear sets as indicated by like reference numbers depicting like components. However, transmission 100 replaces the planetary gear set 16 which is a compound planetary gear set with a simple planetary gear set 160. As described above, planetary gear set 16 is referred to as a compound planetary gear set because planetary gear set 16 has a carrier member that supports two sets of planet or pinion gears 16D and 16E. In contrast, the simple planetary gear set 160 has a carrier member 160B that rotatable supports only one set of planet gears or pinion gears 160D. Further, simple planetary gear set 160 has a sun gear 160C and a ring gear 160A. Moreover, interconnecting member 56 has been eliminated and interconnecting member 48 has been reconfigured as interconnecting member 48′. More specifically, interconnecting member 48′ now connects the ring gear member 160A to carrier member 14B and to the second brake 34. Second brake 34 couples interconnecting member 48′ to the ground or transmission housing 50. Accordingly, the number of other interconnecting members of transmissions 10 and 100 remain the same, however, the length and configuration or shape of the interconnecting members are modified as shown in FIG. 3 to make the required connections between the members of the planetary gear sets and the clutches and brakes.

Referring now to FIGS. 2, 3 and 4, the operation of the embodiment of the eleven speed transmissions 10 and 100 will be described. It will be appreciated that the transmissions 10 and 100 are capable of transmitting torque from the input shaft or member 12 to the output shaft or member 22 in at least eleven forward speed or torque ratios and at least one reverse speed or torque ratio with four overdrives. Each forward and reverse speed or torque ratio is attained by engagement of one or more of the torque-transmitting mechanisms (i.e. first clutch 26, second clutch 28, third clutch 30, first brake 32, second brake 34, third brake 36 and fourth brake 38), as will be explained below. FIG. 4 is a truth table presenting the various combinations of torque-transmitting elements that are activated or engaged to achieve the various gear states. Actual numerical gear ratios of the various gear states are also presented although it should be appreciated that these numerical values are exemplary only and that they may be adjusted over significant ranges to accommodate various applications and operational criteria of the transmissions 10 and 100. An example of the gear ratios that may be obtained using the embodiments of the present invention are also shown in FIG. 4. Of course, other gear ratios are achievable depending on the gear diameter, gear teeth count and gear configuration selected.

With respect to transmission 10, a reverse gear is established by engaging or activating, the second clutch 28, the second brake 34 and fourth brake 38. The second clutch 28 connects the first shaft or interconnecting member 42 with the input shaft or member 12. The second brake 34 connects the seventh shaft or interconnecting member 56 with a stationary element or the transmission housing 50 in order to prevent the seventh shaft or interconnecting member 56 from rotating relative to the transmission housing 50. The fourth brake 38 connects the ninth shaft or interconnecting member 60 with the stationary element or the transmission housing 50 in order to prevent the ninth shaft or interconnecting member 60 from rotating relative to the transmission housing 50. Likewise, the eleven forward ratios are achieved through different combinations of clutch and brake engagement, as shown in FIG. 4.

With respect to transmission 100, a reverse gear is established by engaging or activating, the second clutch 28, the second brake 34 and fourth brake 38. The second clutch 28 connects the first shaft or interconnecting member 42 with the input shaft or member 12. The second brake 34 connects the fourth shaft or interconnecting member 48′ with a stationary element or the transmission housing 50 in order to prevent the fourth shaft or interconnecting member 48′ from rotating relative to the transmission housing 50. The fourth brake 38 connects the ninth shaft or interconnecting member 60 with the stationary element or the transmission housing 50 in order to prevent the ninth shaft or interconnecting member 60 from rotating relative to the transmission housing 50. Likewise, the eleven forward ratios are achieved through different combinations of clutch and brake engagement, as shown in FIG. 4.

It will be appreciated that the foregoing explanation of operation and gear states of the eleven speed transmissions 10 and 100 assumes, first of all, that all the clutches and brakes not specifically referenced in a given gear state are inactive or disengaged and, second of all, that during gear shifts, i.e., changes of gear state, between at least adjacent gear states, a clutch or brake engaged or activated in both gear states will remain engaged or activated.

The description of the invention is merely exemplary in nature and variations that do not depart from the spirit of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention. 

What is claimed is:
 1. A transmission comprising: an input member; an output member; a first planetary gear set having a first, a second and a third member; a second planetary gear set having a first, a second and a third member; a stacked planetary gear set assembly having a first member, a second member, a third member and a fourth member; a first interconnecting member continuously interconnecting the second member of the first planetary gear set with the first member of the second planetary gear set; a second interconnecting member continuously interconnecting the third member of the first planetary gear set with the second member of the second planetary gear set and with the first member of the planetary gear set assembly; and at least seven torque transmitting mechanisms selectively engageable to interconnect at least one of the first, second, third and fourth members of the planetary gear set assembly and at least one of the first, second and third members of the first and second planetary gear sets with another of first, second, third and fourth members of the planetary gear set assembly, another of the first, second and third members of the first and second planetary gear sets and a stationary member, and wherein the at least seven torque transmitting mechanisms are selectively engageable in combinations of at least three to establish at least eleven forward speed ratios and at least one reverse speed ratio between the input member and the output member.
 2. The transmission of claim 1 wherein a first of the seven torque transmitting devices is selectively engageable to interconnect the second member of the first planetary gear set and the first member of the second planetary gear set with the input member.
 3. The transmission of claim 2 wherein a second of the seven torque transmitting devices is selectively engageable to interconnect the first member of the first planetary gear set with the input member.
 4. The transmission of claim 3 wherein a third of the seven torque transmitting devices is selectively engageable to interconnect the third member of the planetary gear set assembly with the input member.
 5. The transmission of claim 4 wherein a fourth of the seven torque transmitting devices is selectively engageable to interconnect the third member of the second planetary gear set with the stationary member.
 6. The transmission of claim 5 wherein a fifth of the seven torque transmitting devices is selectively engageable to interconnect the first member of the second planetary gear set with the stationary member.
 7. The transmission of claim 6 wherein a sixth of the seven torque transmitting devices is selectively engageable to interconnect the first member of the first planetary gear set with the stationary member.
 8. The transmission of claim 7 wherein a seventh of the seven torque transmitting devices is selectively engageable to interconnect the fourth member of the planetary gear set assembly with the stationary member.
 9. The transmission of claim 1 wherein the first planetary gear set is disposed between the second planetary gear set and the planetary gear set assembly.
 10. The transmission of claim 1 wherein the first member of the first planetary gear set, the third member of the second planetary gear set, the first member of the planetary gear set assembly are sun gears, the second member of the first planetary gear set, the first member of the second planetary gear set, the second member of the planetary gear set assembly are carrier members wherein the carrier member of the second planetary gear set rotatable supports a first and second set of planet pinions and wherein the first set of planet pinions mesh with the sun gear and the second set of planet pinions and the second set of planet pinions mesh with the ring gear and the first set of planet pinions and the third member of the first planetary gear set, second member of the second planetary gear set, the third member of the planetary gear set assembly are ring gears.
 11. The transmission of claim 10 wherein the fourth member of the planetary gear set assembly is a gear having an outer surface and an inner surface, wherein the outer surface has a plurality of gear teeth and the inner surface has a plurality of gear teeth.
 12. The transmission of claim 11 wherein the fourth member of the planetary gear set assembly meshes with a first plurality of pinion gears rotatably supported by the second member of the planetary gear set assembly and with a second plurality of pinion gears rotatably supported by the second member of the planetary gear set assembly.
 13. The transmission of claim 1 wherein output member is continuously interconnected with the second member of the planetary gear set assembly.
 14. The transmission of claim 1 wherein four of the seven torque transmitting devices are brakes and three of the seven torque transmitting devices are clutches.
 15. The transmission of claim 1 wherein the stationary member is a transmission housing.
 16. A transmission comprising: an input member; an output member; a first planetary gear set having a first, a second and a third member; a second planetary gear set having a first, a second and a third member; a planetary gear set assembly having a first member, a second member, a third member and a fourth member; a first interconnecting member continuously interconnecting the second member of the first planetary gear set with the first member of the second planetary gear set; a second interconnecting member continuously interconnecting the third member of the first planetary gear set with the second member of the second planetary gear set and with the first member of the planetary gear set assembly; a first torque transmitting mechanism selectively engageable to interconnect the second member of the first planetary gear set and the first member of the second planetary gear set with the input member; a second torque transmitting mechanism selectively engageable to interconnect the first member of the first planetary gear set with the input member; a third torque transmitting mechanism selectively engageable to interconnect the third member of the planetary gear set assembly with the input member; a fourth torque transmitting mechanism selectively engageable to interconnect the third member of the second planetary gear set with the stationary member; a fifth torque transmitting mechanism selectively engageable to interconnect the first member of the second planetary gear set with the stationary member; a sixth torque transmitting mechanism selectively engageable to interconnect the first member of the first planetary gear set with the stationary member; and a seventh torque transmitting mechanism selectively engageable to interconnect the fourth member of the planetary gear set assembly with the stationary member, and wherein the torque transmitting mechanisms are selectively engageable in combinations of at least three to establish at least eleven forward speed ratios and at least one reverse speed ratio between the input member and the output member.
 17. The transmission of claim 16 wherein the fourth member of the planetary gear set assembly is a gear having an outer surface and an inner surface, wherein the outer surface has a plurality of gear teeth and the inner surface has a plurality of gear teeth.
 18. The transmission of claim 17 wherein the fourth member of the planetary gear set assembly meshes with a first plurality of planet pinion gears rotatably supported by the second member of the planetary gear set assembly and with a second plurality of planet pinion gears rotatably supported by the second member of the planetary gear set assembly.
 19. The transmission of claim 18 wherein the first member of the first planetary gear set, the third member of the second planetary gear set, the first member of the planetary gear set assembly are sun gears, the second member of the first planetary gear set, the first member of the second planetary gear set, the second member of the planetary gear set assembly are carrier members wherein the carrier member of the second planetary gear set rotatable supports the first and second set of planet pinions gears and wherein the first set of planet pinions mesh with the sun gear and the second set of planet pinions gears and the second set of planet pinions mesh with the ring gear and the first set of planet pinions gears and the third member of the first planetary gear set, second member of the second planetary gear set, the third member of the planetary gear set assembly are ring gears.
 20. The transmission of claim 18 wherein the first member of the first planetary gear set, the third member of the second planetary gear set and the first member of the planetary gear set assembly are sun gears, the second member of the first planetary gear set, the second member of the second planetary gear set, the second member of the planetary gear set assembly are carrier members and the third member of the first planetary gear set, first member of the second planetary gear set, the third member of the planetary gear set assembly are ring gears.
 21. The transmission of claim 16 wherein the output member is continuously interconnected with the second member of the planetary gear set assembly. 